Completing a marathon to raise a few thousand pounds is a crowning achievement for most amateur fundraisers. But some people prefer a more extreme challenge.
They are not professional athletes or events organisers, but they choose to give up months of their lives to carry out extraordinary feats, raising large amounts for charities in the process.
Sarah Outen, 23, rowed 4,000 miles from Australia to Mauritius, through seas infested by sharks and pirates, losing three stone and setting three world records.
She raised more than £15,000 for Arthritis Care, becoming the biggest fundraiser in the charity's 62-year history. She embarked on the trip in memory of her father, who died suddenly after suffering from arthritis for many years.
"Everyone is delighted that Sarah chose to champion our work through this inspiring voyage," says Rachel Haynes, director of public affairs at the charity. "Like her own solo marathon, living with arthritis is a lonely and painful journey."
Extreme fundraisers may be extraordinary, but they have much in common, says Jack Dykes, a chartered clinical psychologist. Most are aged between 20 and 30. "They are relatively free and not yet tied down by the responsibilities of adult life," he says. "They have a lot of energy and are looking for a challenge."
Endurance feats with superlatives attached - longest, fastest, hardest - are common. "It appeals to them at a competitive, adrenaline- led level," says Dykes. "These are people with a lot of drive."
He estimates that between 2 and 4 per cent of people have the physical and mental capacity to push themselves to such extremes.
Whereas ordinary fundraisers might be happy to sign up to any worthwhile cause, people in this group tend to raise money for charities with which they feel a personal connection. "Capturing these people? I don't know if that's possible," says Dykes. "They have to choose you." Retaining them, however, is possible. "If charities can make it worth their while, they will be very loyal."
Louise Richards, director of policy and campaigns at the Institute of Fundraising, says more and more fundraisers are falling into the 'extreme' group. Those who gain sponsorship of more than £10,000 should be treated in the same way as any major donor, she says.
"Donor care and stewardship are really important," she says. But charities' responses aren't always as good as they might be. "Don't send them a standard letter - give them some kind of special recognition," she says.
"They bring huge scope for press coverage, locally and in the national media. And they have great potential to become the major donors of the future."
DEDICATED - OR A BIT CRAZY?
KATIE SPOTZ, 22
Katie Spotz is a serial extreme fundraiser who has run, swum and rowed all over the world.
Spotz, an American, was the first person to swim the length of the 325-mile Allegheny River in the US.
At one point she became separated from her teammate, who was carrying their kit in a kayak. "I was in the middle of a forest and all I had was a wetsuit," she says. "It took hours to find him again." Running solo across the Mojave and Colorado deserts, she encountered freak snowfall, and coyotes circled around her campfire.
Spotz insists she wasn't particularly athletic at school and was the last to be picked for sports teams. "But when I was in my teens I did a marathon and realised I could do endurance," she says. She cycled from the west to the east coast of the US for Oxfam and, after her grandmother died of lung disease, did a 62-mile ultra-marathon in Australia.
She eventually focused her work on the Blue Planet Run Foundation, which provides clean water to people in developing countries, after experiencing an extreme drought in Melbourne while she was studying there.
"It shocked me that a first-world country could experience water issues," she says. "The foundation is totally transparent - 100 per cent of the donations go directly to the project. I think I will continue to raise money for it. There's no other charity that speaks to me at the moment."
Her next challenge is to row the Atlantic Ocean from Senegal to South America. She intends to raise enough to provide 1,000 people with safe drinking water for life. To cope with isolation, she attends intensive meditation retreats, meditating 12 hours a day for 10 days. If she succeeds, she will become the youngest person to row an ocean solo.
NED GAMMELL, 28
A few years ago, Ned Gammell and 13 friends formed the Galileans, a group that would pull off ambitious projects for charity. "Things you talk about in the pub but say 'there's not enough time' or 'I couldn't possibly do that'," he says. The group's biggest achievements to date are the Great Escape music festival and a pantomime in London's West End.
The group's first founding principle is to raise money. "A very close friend of ours was paralysed in an accident when we were 22, so we decided to raise money for Spinal Research," says Gammell. The second principle is to have fun. "We could make more money if all 14 of us ran a marathon," he says. "But it's not about what we can do to get the biggest cheques. If we do fun stuff that people like being involved with, we hope they will become more interested in the charity."
The festival has raised £26,000 for Spinal Research. The group managed to get beer companies, musicians and production companies involved for free - with the promise of a captive audience of 1,000 young people.
Last winter, the group produced and acted in a pantomime to support Starlight, a charity that grants wishes for sick children. During the show, a young girl with cystic fibrosis was granted her wish - to dance on stage.
The group takes a keen interest in the charities it supports. "We looked closely into them beforehand to make sure we understood what they did," says Gammell. Spinal Research invites the Galileans to its annual fundraising lunches, and the group also has a close relationship with Starlight.
Being a spare-time events planner is challenging. "Lots of nights we'd come home from the day job late and then work until the early hours," says Gammell. "But it's the most rewarding thing we've done in our lives."
SAM WILLIAMS, 25
"I've always liked to try things when I don't know whether I can do them or not," says Sam Williams, a law student from Bath.
When he started university he discovered rowing, and set himself the goal of rowing across the Atlantic. He shortlisted 10 charities using the Justgiving website. "I wanted a small to medium-sized charity that I and most people hadn't heard of," he says.
Williams settled on FARM-Africa, which helps African farmers make their own living from the land. "The problem with aid is that a lot of people do it the wrong way," he says. "On the whole, FARM-Africa does it the right way."
This year, Williams did a three-month, 5,000-mile fundraising bicycle ride from London to Kenya, via Europe, Syria, Egypt, Sudan and Ethiopia, to visit a FARM-Africa project. "I wanted to see for myself what they were doing," he says.
The trip was rarely dull. Along the way, Williams was almost robbed of all his possessions in Hungary and stayed in the British ambassador's house in Jordan.
His next ideas include a giant triathlon and climbing to the highest point in every US state. He admits to being "a bit disappointed" by what he perceived as a lack of support for fundraising and gaining media coverage.
Having raised £26,000 for FARM-Africa, he says next time he might choose a different cause: "I had hoped they would generate a bit more publicity once I got to Africa. You have only a small window."